THERMAL-CONDUCTIVITY OF DIAMOND BETWEEN 170 AND 1200-K AND THE ISOTOPE EFFECT

Measurements on the thermal conductivity of natural and synthetic sing le-crystal diamond are presented over a wide temperature range. The la rge isotope effect reported previously has been confirmed. The data ha ve been analyzed using both the Debye model of thermal conductivity, w hich ignores the N processes, and the Callaway model in the limit that the N processes dominate the phonon scattering. It is found that the observed isotope effect can be accounted for by including the N proces ses alone, without having to postulate the existence of additional def ects.